Eeeek, Red Battery light.

[AV8R4AA]

I rarely drive the 4.6is.
I took it out after 3 weeks of sitting.
For maybe 2 seconds I got a red battery light.
That was on the 15 miles drive home.

It is chilly here and I had all 4 bun warmers on.
Stereo blaring, headlights on.

As quick as it showed, it disappeared.
No electrical abnormalities, just a quick on, then off.
6 month old Interstate battery, 1 year old alternator.

Any reason for panic here?

[williamx5]

Good day!

Well, I would say no, but I would pull out the volt meter and verify you are getting close to or over 14V when running... If it is under 13V, you may need to break out the warranty info on the alt... I have a good voltage regulator around the shop somewhere... If you wanted to tear yours apart... Not too terribly hard to do...

Cheers!!

[StephenVA]

Test don't guess
Volt meter on battery key off
Volt meter on battery at idle
Volt meter on battery at 1500 RPM
Trash on the alternator bushes water moisture etc can cause a blip and then as the engine warms everything up all goes to normal. Nothing to panic over.
Q - new or reman alternator?

[Calipsoe]

Probably nothing to worry about. For some reason I usually get the red battery light when the temperatures are above 65 degrees. When I check the voltage via the instrument cluster diagnostic test I get an average reading of 13.6v so I know the battery is charging even though the light is on. If the test shows 12v or under the battery is not getting charged.

You can check the voltage using the instrument cluster diagnostic test #9.
You will need to unlock the test by using your VIN number.

All the info is here to access the diagnostic test is here:
BMW X5 - Access the Hidden Onboard Computer (OBC) Functions.

Or here if you prefer video:
https://www.youtube.com/watch?v=dRDBKn4jn5Y

[X53Jay4.8is]

when it comes on permanently then you can properly diagnose the situation.

[andrewwynn]

When did the light come on? If happened right as coming to a stop I would suspect the alternator. (watch your voltage real-time when coming to a stop). I had a loose alternator bolt so look for that also.


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[Calipsoe]

FYI you can monitor the battery voltage while you are driving using the instrument cluster diagnostic test #9.
You will need to unlock the test by using your VIN number.

All the info to access the diagnostic test is here:
high cluster: http://www.xoutpost.com/1007582-post12.html
low cluster: http://www.xoutpost.com/1007645-post17.html

Or here if you prefer video:
https://www.youtube.com/watch?v=dRDBKn4jn5Y

[andrewwynn]

E53 doesn't need the VIN just choose menu 19 to unlock


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[wpoll]

Originally Posted by andrewwynn

E53 doesn't need the VIN just choose menu 19 to unlock


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You sure? Mine needed unlocking... and does after each time I pull the battery.

I just enter the sum of the last five number in my VIN (24 fwiw..) in menu #19 and then the other menus are unlocked.

[andrewwynn]

Maybe I had it backwards. I don't have to VIN unlock just menu 19. I have low cluster 2001. Wife's is the same.